【摘 要】
：
Nearfield acoustic holography in a moving medium is a technique which is typically suitable for sound sources iden-tification in a flow.In the process of sound field reconstruction,sound pressure is usually used as the input,but it may contain considerabl
【机 构】
：
Department of Mechanical & Electrical Engineering School,Anhui Jianzhu University,Hefei 230601,China
论文部分内容阅读
Nearfield acoustic holography in a moving medium is a technique which is typically suitable for sound sources iden-tification in a flow.In the process of sound field reconstruction,sound pressure is usually used as the input,but it may contain considerable background noise due to the interactions between microphones and flow moving at a high velocity.To avoid this problem,particle velocity is an alternative input,which can be obtained by using laser Doppler velocimetry in a non-intrusive way.However,there is a singular problem in the conventional propagator relating the particle velocity to the pressure,and it could lead to significant errors or even false results.In view of this,in this paper,nonsingular propagators are deduced to realize accurate reconstruction in both cases that the hologram is parallel to and perpendicular to the flow direction.The advantages of the proposed method are analyzed,and simulations are conducted to verify the validation.The results show that the method can overcome the singular problem effectively,and the reconstruction errors are at a low level for different flow velocities,frequencies,and signal-to-noise ratios.
其他文献
We report the fabrication of long period gratings in fluid-cladding microfibers by directly focusing a femtosecond laser beam on the microfibers surface to induce periodical modification a long one side of the microfibers.A long period grating is fabricat
A solvable model of lateral line of a fish based on a wave equation with additional boundary conditions on a set of isolated points is proposed.Within the framework of this model it is shown that the ratio of pressures on lateral lines on different fish f
Laser-induced plasmas of dual-pulse fiber-optic laser-induced breakdown spectroscopy with different pulse energy ratios are studied by using the optical emission spectroscopy (OES) and fast imaging.The energy of the two laser pulses is independently adjus
A dual-passband single-polarized converter based on the band-stop frequency selective surface (FSS) with a low radar cross-section (RCS) is designed in this article.The unit cell of the proposed converter is formed by a polarization layer attached to the
Topological quantum states have attracted great attention both theoretically and experimentally.Here,we show that the momentum-space lattice allows us to couple two Su-Schrieffer-Heeger (SSH) chains with opposite dimerizations and staggered interleg hoppi
Bright single-photon emitters (SPEs) are fundamental components in many quantum applications.However,it is difficult to simultaneously get large Purcell enhancements and quantum yields in metallic nanostructures because of the huge losses in the metallic
The hidden Z2 symmetry of the asymmetric quantum Rabi model (AQRM) has recently been revealed via a systematic construction of the underlying symmetry operator.Based on the AQRM result,we propose an ansatz for the general form of the symmetry operators fo
The relation between friction mechanism and force chains characteristics has not yet been fully studied in the pow-der metallurgy research area.In this work,a uniaxial compression discrete element model is established based on the compaction process of fe
Microwave-induced thermoacoustic tomography (TAT) is a rapidly-developing noninvasive imaging technique that integrates the advantages of microwave imaging and ultrasound imaging.While an image reconstruction algorithm is critical for the TAT,current reco
The terahertz technology has attracted considerable attention because of its potential applications in various fields.However,the research of functional devices,including polarization converters,remains a major demand for practical ap-plications.In this w